Under that theory, the city’s primarily white neighborhoods will vote for a white mayoral candidate; the city’s primarily non-white neighborhoods will vote for a non-white one. Because of entrenched voter loyalties, when the preliminary battle between eight white and eight non-white candidates is over, the final election field will feature one white and one non-white finalist.

At least for the preliminary, such thinking has credibility, mostly because in Boston, neighborhood politics still dominate campaigns. Winners are the ones who turn out their neighborhood base. And here’s the truth about Boston in 2013: Racial makeup still defines neighborhoods. That means that to a great degree, racial makeup still defines a politician’s base.

A study of 2010 Census data by John Logan of Brown University and Brian Stults of Florida State University has been making the rounds of tweetersand bloggers. It scores Boston as “very high segregation.” An accompanying map breaks down Census data to show a concentration of blue dots — the city’s black residents — in one area. A concentration of red dots — the city’s white residents — surround them, with sprinkles of orange dots, representing Hispanics, and green dots, representing Asians.

Turn out the blue, orange, and green dots, and you have a chance of fulfilling the prophecy of a non-white candidate finishing in at least one of the top two spots.

If it holds true on Sept. 24 — preliminary election day — what happens next could show how much Boston has changed.

And here’s the truth about Boston in 2013: Racial makeup still defines neighborhoods.

In March 2011, Mayor Thomas M. Menino — the city’s first Italian-American mayor — announced that based on 2010 US Census data, Boston is a majority-minority city; 53 percent of the population is non-white or Hispanic. In November 2011, at-large City Councilor Ayanna Pressley topped the ticket, becoming the first woman and first African-American to do so. Felix Arroyo — who is one of the 16 people now running for mayor — came in second.

That new face of Boston sets up the possibility of electing the city’s first non-white mayor. But does anyone really want a 2013 Boston mayor’s race to be cast in such retro terms, as a showdown between white and non-white voters?

That’s so 1983, when Raymond L. Flynn of South Boston ran against Mel King, the African-American who stunned Boston by finishing second in the preliminary election.

Flynn won the general with 65 percent of the final election tally. But today, he rejects the conventional wisdom that race determined the outcome. He also rejects the conventional wisdom that race will determine the outcome in the 2013 mayoral preliminary election.

“This did not happen in 1983 for the reason most people think — so-called ‘identity politics’ based on race,” he said. “It happened because Mel and I were talking about — and had a record on — the issues most people cared about — affordable housing, condo conversion, using linkage to spread the wealth of the downtown to the neighborhoods.”

Added Flynn: “It won’t necessarily happen in 2013, either. It will depend on the two candidates who choose to get behind the issues people most care about — and many of those are still the same issues.”

Put another way, Flynn is saying people vote on the basis of more race-neutral questions of self-interest: Who best understands the problems of people like me? Who will do the most to help people like me? Back in 1983, the test was more about skin color than Flynn wants to accept. But it may be very different in 2013. After all, Deval Patrick twice won election as governor of a state whose population is 84 percent white.

A black, Latino, or female mayor would surely be a breakthrough for Boston. It would shake up the power structure and energize neighborhoods that are cut off, geographically and psychologically, from the rest of Boston. It’s even possible two non-white candidates could face off in the final election.

But just talking about it like that shows how far the city has to go to get from One Boston in tragedy to One Boston in politics.

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